Demystifying the Technical Side of Mixing

Looking at the various jobs in the business of Post Production sound, re-recording mixing seems to carry an air of mystique. It’s an intimidating task, even for an experienced sound editor, to make the jump to the console. There seems to be so much that can go wrong. So many small factors that need to be accounted for simply to make the gear work. It’s true, there are hundreds of details to be aware of, but with some basic tips we can pull back the curtain on some of the more daunting technical aspects, allowing you to put aside trepidation and make the gear work for you.

Metering

Meters can be your best friends. Yes, as a mixer it’s best to develop an ear for where things should live in the mix without relying on technology. And you will. But without meters to give you a ballpark as you start your career, you’ll be completely in the dark. Get yourself a good set of stereo and surround meters. I like the Insight meter by iZotope. Remember that digital meters are customizable. You can set peak and average settings inside the meters so they adjust visually, giving you clues to help you stay on track. As a bonus, by using the Analyze button in the Audiosuite version you’ll have the tools you need on hand to digitally check your mix in a fraction of real time to be sure you are on spec once you finish.

Reading a Spec Sheet

Before starting any new project, the first request you should make is for a spec sheet. This will be your blueprint as you create (or alter) a mix template for the project. Spec sheets will come in all different shapes, sizes and formats, intended to cover every aspect of the project. It helps to know what you’re looking for. Start by checking the contents for a section labeled AUDIO. Once located, here are some key words to seek out:

Audio Codec, Sample rate and Bitrate

Does the client want .WAV files or .AIFf? 44.1kHz or 48kHz? These are simple settings you can apply before beginning your mix to make sure you comply.

Average Audio Levels

The average audio for the length of the program, from your main title through the end credits can be denoted here as a simple reference level (i.e. -20dBfs), or a dialogue normalization (dialnorm) level (also denoted as LKFS). Basically once you finish your mix, you’ll want to run a meter on the final stems to see if you are on point.

Peak Audio Levels

Your peak level is the loudest the mix can get an any given time. To be safe, you’ll want to have a limiter in place for any tracks sending audio to your final printed stems with this level set for the Threshold and Ceiling. I like Avid’s Pro Limiter for this, but any good true peak meter should work well.

Working With a Template

The real beauty in mixing lies within the mix template. There are literally thousands of ways to customize your workflow. Your template is simply an expression of how best you like to work. But don’t let the enormity of options overwhelm you. The truth is, you can mix without a very complex template, simply moving the audio from point A (the source tracks) to point B (your final mix stems) and get great results if you have a good ear. So don’t sweat the details. Use templates to make your life easier not scarier. Any tool you’ve got a solid technical grasp on that will help speed up your workflow while improving the work is a win in my book. Here are some of my favorites:

VCA Master’s

You can group any number of tracks and control them with a global volume fader that will not use up any of your pro tools voices. That’s what VCA’s are for. All automation is applied as a behind the scenes trim that won’t change the original automation pass. I like to split my editorial up into food groups, assigning a VCA to each group within my mix template. This makes global moves (like “lets turn down the swishes”) a cinch.

AUX Inputs

What if you want to add compression or EQ or another effect to an entire group? Auxiliary inputs make this possible. Do keep in mind that each voice in an AUX input counts for a voice in the overall Pro Tools session so you’ll want to keep these in check if you are conserving horsepower.

Memory Locations for View Optimization

You can create custom views for yourself by simply utilizing the check boxes labeled Track Show/Hide and Track Heights in the memory locations window. Get the tracks you want (and only want) in view and sized correctly, then create a new memory location checking these boxes. As you’re mixing, you can dial up these locations as you would any other and your view will change to reflect your customization. Even just setting these views for Dialogue, Music and Sound Effects makes a world of a difference. You’ll be moving through the mix super fast, jumping you to exactly where you need to be instead of constantly scrolling up and down through your session.

LFE Sweetener

This is a fun one. Add a send to bus all of your sound effects tracks through an AUX that has an LFE sweetener (I like Lowender). Even on the most basic of settings with a very light send, your mix will feel different. This is a great way to help achieve that 'fuller' and ‘bigger’ quality without being too bottom heavy; especially useful for action shows. Try the same treatment with your music tracks, using the level of the Aux to adjust from cue to cue if necessary.

Setting Multiple Track Outputs

By holding down the Control button, you can add multiple outputs to a single track. This is denoted by a small + sign in the output. This is perfect for sending Music, for example, to the final comp, music and M&E stem tracks all at once. If you set this up correctly, you can have all your tracks ready to print all at once, saving you hours of work on multiple printing passes.

Dummy Outputs

Most spec sheets require at a minimum a Print Master (full mix) and M&E (Music and Effects only) delivery. When it comes time to print your final stems, I suggest you do them all at once. You’ll need active channel outputs to print on a track but definitely don’t want to be hearing them all play back together. This is where dummy outputs come in. Create a mono BUS called DUMMY that you never route to another track and set this as the output for every track except your Print Master (which you’ll monitor through). This is an elegant solution, saving you the trouble of toggling mute buttons as you run through your mix.

Destructive Punch

I could write an entire post on destructive punch (and may do that) but the long and short of it is, if you learn how to properly set up DP in Pro Tools, you can save yourself a lot of time. All my shows have an Executive playback, where we play through the entire mix without stopping for a final notes pass. I like to use this time to do my printing, taking advantage of Destructive Punch mode to then punch in any fixes. If all goes well, I’m home 22 minutes earlier than if I wait to print until after the clients have left.

KnowING Your Audience

The second question you’ll want to ask your clients (after requesting a spec sheet) is where the project be seen. Knowing whether this short film will play in theaters at film festivals or exclusively online should ultimately affect the choices you make in the mix. For example, we tend to mix TV much less dynamically than film. A whisper on a TV show is usually mixed relatively loud, and for good reason. In a movie theater, you have a captive audience in a quiet room hanging on every line. A TV show could be consumed with any manner of noise squawking behind the viewer. A running vacuum, a fight among siblings, the microwave… the ambient noises of every day life could make a soft whisper inaudible. Knowing where your show is airing will inform you on how to tailor the experience to the viewer.

Preparing Deliverables

Making great deliverables should be the easy part. All the details you need are in the spec sheet and you’ve applied these details to your workflow and template to ensure you’ll be on track. Here are some final tips:

Using 2 Pops as a Checkpoint

Place a 2pop (a one frame one kHz tone placed two seconds before the first frame of picture) on each of the master Aux tracks in your template. Before printing anything else, simply print the 2pop. Take a look at your stem tracks. Are all the pops in sync? Do they all appear to be even in volume? If so, you’re probably on the right track. Just be sure to audibly check each and every one of your stems to be sure they have the correct materials (i.e. the M&E tracks should not contain any dialogue). At least for the first time you mix. Trust me, you’ll sleep better that night.

Labeling

It’s likely the client or spec sheet will dictate the proper labeling scheme for each project. If however they do not specify, I suggest you at least include the Project Name (or show code), the type of stem and a version number on every one of your stems.

Final Checklist

I’m not going to lie, it helps to be a bit crazy for the details. The last check I make is in the Audio Files folder itself. Sort the files by Date Modified. Since the last thing you did was print your stems, this should bring all of them to the top of the window. Take a look and be sure all of your labeling is correct. I also like to look at the file size to ensure they are all exactly the same. If you’ve got a file that doesn’t match in size, something went wrong with your print.

Yes, this is a ton of information. And yes, it can be a bit daunting to take it all on. But none of this is terribly complicated. If you have an eye for the details, an ear good sound and the drive to learn, you can implement these tools and workflow enhancements as you grow, making the jump into re-recording mixing without fear.

Do you have any tips for the novice mixer? Share your thoughts in the comments below.